Strap wrench



Aug. 4, 1959 w. J. RozMus 2 sheets-sheet 1 Filed Feb. 1s,l 1957 IN VEN TOR. WLTEE f BOZ/705'.

Aug. 4, 1959 W. J. RozMUs STRAP WRENCH 2 Sheets-Sheet 2 Filed Feb. 13, 1957 INVENTOR. WHLTEE J P02/W05. BY /V l (7m/wy niteci States Patenti STRAP WRENCH Walter J. Rozmus, Whitesboro, N.Y., assignor to Utica Drop Forge & Tool Corp., Utica, N.Y., a corporation of New York p Application February 13, '1957, Serial No. 639,995

4 Claims. (Cl. 81-64) `This invention relates in general to wrench tools, and relates more specifically to a flexible band and to a drive handle to adjust the band to size, the handle also serving to twist the band whileproducing a gripping holding action.

Large round objects are Adifficult to grip without marring the surface with gripping jaws or crushing a thin shell. A particular instance of a device having no particular gripping surface is a cartridge oil filter for an automotive vehicle. At least one embodiment of such an oil filter comprises an exterior housing which must be tightly threaded into a receiving holder, and must be released by reversing the direction of rotation. Such structures are relatively light weight material and accordingly cannot withstand the concentrated pressure of jawed wrench devices.

Furthermore, and a more particular problem, is the fact that the diameter of various lters of this type vary widely in diameter. Any friction wrench used on such devices must be able to compensate readily for such diameter differences.

In the past, the attempted devices for producing a suitable self-adjusting friction-type band wrench required considerable machine operation and complex designs which resulted iny highly concentrated stress riser points that led to sudden drive handle failure. Such failure often results in bruised hands of the operator. Furthermore, machined structures of such type require massive drive handles as well as being expensive and difficult to produce.

Therefore, a primary object of the present invention is to provide a drive handle for a friction grip loop, which drive handle is completely free of stress riser machined portions.

Another object of the present invention is to provide a relatively shiftable pivot area for one end of such a flexible strap.

And another object of the present invention is to provide a simplified drive handle construction having maximum strength for a minimum of handle weight.

Other objects and a fuller understanding of the invention may be had by referring to the following description and claims, taken in conjunction with the accompanying drawings, in which:

Figure l is a side View of the device illustrating the yoke nature of the strap ends and the band whip of the grasping strap;

Figure 2 is a plan View of the strap illustrating the improved drive handle formation; and,

Figure 3 is a side view of an alternate construction for heavy duty use.

The preferred embodiment of the invention is set forth in the drawing.

This preferred embodiment comprises a handle indicated generally by the reference character 10. The handle has `a knurled grip 'end 11 and a drive end 12. The drive end is characterized by a general over-all S curve formation. The drive end may be said to begin at a first reverse bend 13 which serves as a general divi- Patented Aug. 4, 1959 ice sion between the two portions. The reverse bend 13 is significant in the present invention. This reverse bend 13 forms and denes a cradle recess 14. Cradle recess 14 is closed in an angular relationship of less than The inner surfaces as shown in Figure 2 slope toward the apex of the cradle recess 14.

A second reverse bend 15 completes the general S curve formation. The forward end of the handle 10 is provided with a pivot cross pin 16. The forward end of the handle 10 is provided with a pivot cross pin 16. The forward end of the bar from which the handle 10 is made is perfectly machined to produce a reduced end 17 prior to the bending of the drive end. Pin .16 is drilled and may therefore be slipped upon the end 17 and peened or otherwise secured in place.

A cradle pin 1S is cradled in the cradle recess 14.

A flexible strap 19, usually of thin sheet metal, is provided with a rst yoke and 20 having a slot 21 dividing two pin embracing loops 22. The loops 22 are engaged over the ends of the cross pin 16 and therefore provide a pivotal hanging connection of the strap 19 to the pivot cross pin 16 at the forward end of the tool. Pin 16 provides a pivotal relationship at a fixed point, and therein differentiates from the moveability of the pin 18 at the cradle recess 14.

The second end of the flexible strap 19 is provided with a second yoke end 23 having a slot 25 separating the end into loops 24. The body of -the handle 10 resides within the slot 25, or stated otherwise, the loops 24 are positioned around the body of the handle .10. In any event, the loops 24 engage opposite ends of the cradle pin 18. Accordingly, the pin 18 may be said to reside within the cradle recess 14, or may be stated to be carried by the end of the flexible strap v19. Both situations are correct. However, a degree of mobility is available for the second yoke end 23 because the slot 25 will permit the second end 23 and the cradle pin 18 to move out of the apex position in the cradle recess 14. Such movement is often useful in the operation of devices of this nature, and this invention is believed to be the rst wrench to provide such shiftability in a second pivot point.

The pivot cross pin 16 is always in a forward position with respect to the location of the cradle pin 18. The formation of the drive end of handle 10 is such that contact of the pivot cross pin 16 will take place with the body of the strap 19 before the intermediate portion 26 between the rst and second reverse bends reaches a perpendicular position with respect to the pulling force acting upon the pin 18. This pulling force is represented, of course, by the actual portion of the flexible strap 19 in the area of the second yoke end. Thus, the S-curve formation will constantly urge the pin 18 into Ithe recess 14 and will never reach a position whereby any component of force will urge the pin 18 to move by its own volition toward the second reverse bend 15.

iThe Figure 3 illustrates an alternate embodiment sometimes found to be preferable, particularly for use with very `thin walled lter housings, or for driving under conditions requiring considerable force.

y"Ihe embodiment of Figure 3 is constructed essentially as the Figure 1 embodiment, with the addition of a pressure plate 27 under the area of drive end 12. Pressure plate 27 is a more riclged member and is curved to substantially conform to the curvature of the workpiece, and will spread the gripping load over a larger area. The contact surfaces may be roughened, if desired, for anti-slip characteristics.

Although the invention has been described in its preferred form with a certain degree of particularity, it is understood that the present disclosure of the preferred form has been made only by way of example and that numerous changes in the details of construction and the combination and arrangement of parts may be resorted to without departing from the spirit and the scope of the invention as hereinafter claimed.

What is claimed is:

1. A strap wrench, comprising, a ridged actuation handle having a hand grip end portion and a drive end portion, said handle being a bar having a first reverse bend creating a cradle recess, a second reverse bend forward of the rst bend, said drive end portion thereby having a general S curve shape, a pivot cross pin carried at the forward end of the drive end portion, a cradle pin cradled in said cradle recess, a exible strap having a lirst yoke end with spaced loop portions wrapped around opposite ends of said pivot cross pin, said strap having a second yoke end with spaced loop portions wrapped around opposite ends of the cradle pin, said second end of the strap having a slot between the spaced loop portions, said handle bar passing through said slot, whereby said strap second end is pivotally slung in said first recess bend and is free to be shifted along the handle away from the deepest portion of said rst reverse bend.

2. A strap wrench, comprising, a rigid actuation handle having a hand grip portion and a drive end portion, said handle being a bar and said drive end portion being generally S shaped beginning at a reverse bend from the handle, said reverse bend creating a cradle recess, a pin cradled in said recess, a flexible strap having a first end pivotally connected to the forward end of the drive end portion, said strap having a second end, said pin carried by said strap laterally of said second end, said second end of the strap having a slot separating the end into two spaced portions, said handle bar passing through said slot, whereby said strap second end is pivotally slung in said recess bend, and is free to be shifted along the handle away from the deepest portion of said reverse bend.

3. A strap wrench as defined in claim 2, wherein said hand grip portion has a longitudinal axis and said forward end of the handle drive end portion is located forward of said cradle to one side of an extension of the hand grip portion axis.

4. A strap wrench as defined in claim 2, wherein a stiff pressure plate is carried by said forward end, said stiff pressure plate curved to substantially conform to the intended workpiece and thereby dissipate the pressure of the strap at ythe pivot area and prevent excessive pressure concentration.

References Cited in the tile of this patent UNITED STATES PATENTS 771,376 Loxterkamp Oct. 4, 1904 822,652 Corsey June 5, 1906 994,953 Robbins June 13, 1911 1,324,494 Carpenter Dec. 9, 1919 1,523,228 Marke Jan. 13, 1925 

